SVN Externals - cannot get to work in IDEA 9

I'm trying to get svn:externals to work via the IDE and am having trouble.  I can add the property to the directory but, when doing an update, the external resource does not get pulled in.

Here's the scenario, as close as I can get it:

svn repository setup:
     https://svnserver/projectA     

• /trunk
  • /lib
    • /vendor
    • some.jar

I defined svn:externals via a property of the "/lib" directory with a value as follows: "vendor https://svnserver/projectA/trunk/lib/some.jar".  This property, I assume, upon update should leave a copy of "some.jar" in the /lib/vendor directory, but it does nothing..

Any thoughts as to what I've done wrong?

Thanks.